1.TH "libunbound" "3" "Mar 21, 2013" "NLnet Labs" "unbound 1.4.20"
| 1.TH "libunbound" "3" "Mar 12, 2014" "NLnet Labs" "unbound 1.4.22"
|
2.\"
3.\" libunbound.3 -- unbound library functions manual
4.\"
5.\" Copyright (c) 2007, NLnet Labs. All rights reserved.
6.\"
7.\" See LICENSE for the license.
8.\"
9.\"
10.SH "NAME"
11.LP
12.B libunbound,
13.B unbound.h,
14.B ub_ctx,
15.B ub_result,
16.B ub_callback_t,
17.B ub_ctx_create,
18.B ub_ctx_delete,
19.B ub_ctx_set_option,
20.B ub_ctx_get_option,
21.B ub_ctx_config,
22.B ub_ctx_set_fwd,
23.B ub_ctx_resolvconf,
24.B ub_ctx_hosts,
25.B ub_ctx_add_ta,
26.B ub_ctx_add_ta_file,
27.B ub_ctx_trustedkeys,
28.B ub_ctx_debugout,
29.B ub_ctx_debuglevel,
30.B ub_ctx_async,
31.B ub_poll,
32.B ub_wait,
33.B ub_fd,
34.B ub_process,
35.B ub_resolve,
36.B ub_resolve_async,
37.B ub_cancel,
38.B ub_resolve_free,
39.B ub_strerror,
40.B ub_ctx_print_local_zones,
41.B ub_ctx_zone_add,
42.B ub_ctx_zone_remove,
43.B ub_ctx_data_add,
44.B ub_ctx_data_remove
| 2.\"
3.\" libunbound.3 -- unbound library functions manual
4.\"
5.\" Copyright (c) 2007, NLnet Labs. All rights reserved.
6.\"
7.\" See LICENSE for the license.
8.\"
9.\"
10.SH "NAME"
11.LP
12.B libunbound,
13.B unbound.h,
14.B ub_ctx,
15.B ub_result,
16.B ub_callback_t,
17.B ub_ctx_create,
18.B ub_ctx_delete,
19.B ub_ctx_set_option,
20.B ub_ctx_get_option,
21.B ub_ctx_config,
22.B ub_ctx_set_fwd,
23.B ub_ctx_resolvconf,
24.B ub_ctx_hosts,
25.B ub_ctx_add_ta,
26.B ub_ctx_add_ta_file,
27.B ub_ctx_trustedkeys,
28.B ub_ctx_debugout,
29.B ub_ctx_debuglevel,
30.B ub_ctx_async,
31.B ub_poll,
32.B ub_wait,
33.B ub_fd,
34.B ub_process,
35.B ub_resolve,
36.B ub_resolve_async,
37.B ub_cancel,
38.B ub_resolve_free,
39.B ub_strerror,
40.B ub_ctx_print_local_zones,
41.B ub_ctx_zone_add,
42.B ub_ctx_zone_remove,
43.B ub_ctx_data_add,
44.B ub_ctx_data_remove
|
45\- Unbound DNS validating resolver 1.4.20 functions.
| 45\- Unbound DNS validating resolver 1.4.22 functions.
|
46.SH "SYNOPSIS"
47.LP
48.B #include <unbound.h>
49.LP
50\fIstruct ub_ctx *\fR
51\fBub_ctx_create\fR(\fIvoid\fR);
52.LP
53\fIvoid\fR
54\fBub_ctx_delete\fR(\fIstruct ub_ctx*\fR ctx);
55.LP
56\fIint\fR
57\fBub_ctx_set_option\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR opt, \fIchar*\fR val);
58.LP
59\fIint\fR
60\fBub_ctx_get_option\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR opt, \fIchar**\fR val);
61.LP
62\fIint\fR
63\fBub_ctx_config\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR fname);
64.LP
65\fIint\fR
66\fBub_ctx_set_fwd\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR addr);
67.LP
68\fIint\fR
69\fBub_ctx_resolvconf\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR fname);
70.LP
71\fIint\fR
72\fBub_ctx_hosts\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR fname);
73.LP
74\fIint\fR
75\fBub_ctx_add_ta\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR ta);
76.LP
77\fIint\fR
78\fBub_ctx_add_ta_file\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR fname);
79.LP
80\fIint\fR
81\fBub_ctx_trustedkeys\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR fname);
82.LP
83\fIint\fR
84\fBub_ctx_debugout\fR(\fIstruct ub_ctx*\fR ctx, \fIFILE*\fR out);
85.LP
86\fIint\fR
87\fBub_ctx_debuglevel\fR(\fIstruct ub_ctx*\fR ctx, \fIint\fR d);
88.LP
89\fIint\fR
90\fBub_ctx_async\fR(\fIstruct ub_ctx*\fR ctx, \fIint\fR dothread);
91.LP
92\fIint\fR
93\fBub_poll\fR(\fIstruct ub_ctx*\fR ctx);
94.LP
95\fIint\fR
96\fBub_wait\fR(\fIstruct ub_ctx*\fR ctx);
97.LP
98\fIint\fR
99\fBub_fd\fR(\fIstruct ub_ctx*\fR ctx);
100.LP
101\fIint\fR
102\fBub_process\fR(\fIstruct ub_ctx*\fR ctx);
103.LP
104\fIint\fR
105\fBub_resolve\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR name,
106.br
107 \fIint\fR rrtype, \fIint\fR rrclass, \fIstruct ub_result**\fR result);
108.LP
109\fIint\fR
110\fBub_resolve_async\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR name,
111.br
112 \fIint\fR rrtype, \fIint\fR rrclass, \fIvoid*\fR mydata,
113.br
114 \fIub_callback_t\fR callback, \fIint*\fR async_id);
115.LP
116\fIint\fR
117\fBub_cancel\fR(\fIstruct ub_ctx*\fR ctx, \fIint\fR async_id);
118.LP
119\fIvoid\fR
120\fBub_resolve_free\fR(\fIstruct ub_result*\fR result);
121.LP
122\fIconst char *\fR
123\fBub_strerror\fR(\fIint\fR err);
124.LP
125\fIint\fR
126\fBub_ctx_print_local_zones\fR(\fIstruct ub_ctx*\fR ctx);
127.LP
128\fIint\fR
129\fBub_ctx_zone_add\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR zone_name, \fIchar*\fR zone_type);
130.LP
131\fIint\fR
132\fBub_ctx_zone_remove\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR zone_name);
133.LP
134\fIint\fR
135\fBub_ctx_data_add\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR data);
136.LP
137\fIint\fR
138\fBub_ctx_data_remove\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR data);
139.SH "DESCRIPTION"
140.LP
141.B Unbound
142is an implementation of a DNS resolver, that does caching and
143DNSSEC validation. This is the library API, for using the \-lunbound library.
144The server daemon is described in \fIunbound\fR(8).
145The library can be used to convert hostnames to ip addresses, and back,
146and obtain other information from the DNS. The library performs public\-key
147validation of results with DNSSEC.
148.P
149The library uses a variable of type \fIstruct ub_ctx\fR to keep context
150between calls. The user must maintain it, creating it with
151.B ub_ctx_create
152and deleting it with
153.B ub_ctx_delete\fR.
154It can be created and deleted at any time. Creating it anew removes any
155previous configuration (such as trusted keys) and clears any cached results.
156.P
157The functions are thread\-safe, and a context an be used in a threaded (as
158well as in a non\-threaded) environment. Also resolution (and validation)
159can be performed blocking and non\-blocking (also called asynchronous).
160The async method returns from the call immediately, so that processing
161can go on, while the results become available later.
162.P
163The functions are discussed in turn below.
164.SH "FUNCTIONS"
165.TP
166.B ub_ctx_create
167Create a new context, initialised with defaults.
168The information from /etc/resolv.conf and /etc/hosts is not utilised
169by default. Use
170.B ub_ctx_resolvconf
171and
172.B ub_ctx_hosts
173to read them.
| 46.SH "SYNOPSIS"
47.LP
48.B #include <unbound.h>
49.LP
50\fIstruct ub_ctx *\fR
51\fBub_ctx_create\fR(\fIvoid\fR);
52.LP
53\fIvoid\fR
54\fBub_ctx_delete\fR(\fIstruct ub_ctx*\fR ctx);
55.LP
56\fIint\fR
57\fBub_ctx_set_option\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR opt, \fIchar*\fR val);
58.LP
59\fIint\fR
60\fBub_ctx_get_option\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR opt, \fIchar**\fR val);
61.LP
62\fIint\fR
63\fBub_ctx_config\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR fname);
64.LP
65\fIint\fR
66\fBub_ctx_set_fwd\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR addr);
67.LP
68\fIint\fR
69\fBub_ctx_resolvconf\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR fname);
70.LP
71\fIint\fR
72\fBub_ctx_hosts\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR fname);
73.LP
74\fIint\fR
75\fBub_ctx_add_ta\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR ta);
76.LP
77\fIint\fR
78\fBub_ctx_add_ta_file\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR fname);
79.LP
80\fIint\fR
81\fBub_ctx_trustedkeys\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR fname);
82.LP
83\fIint\fR
84\fBub_ctx_debugout\fR(\fIstruct ub_ctx*\fR ctx, \fIFILE*\fR out);
85.LP
86\fIint\fR
87\fBub_ctx_debuglevel\fR(\fIstruct ub_ctx*\fR ctx, \fIint\fR d);
88.LP
89\fIint\fR
90\fBub_ctx_async\fR(\fIstruct ub_ctx*\fR ctx, \fIint\fR dothread);
91.LP
92\fIint\fR
93\fBub_poll\fR(\fIstruct ub_ctx*\fR ctx);
94.LP
95\fIint\fR
96\fBub_wait\fR(\fIstruct ub_ctx*\fR ctx);
97.LP
98\fIint\fR
99\fBub_fd\fR(\fIstruct ub_ctx*\fR ctx);
100.LP
101\fIint\fR
102\fBub_process\fR(\fIstruct ub_ctx*\fR ctx);
103.LP
104\fIint\fR
105\fBub_resolve\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR name,
106.br
107 \fIint\fR rrtype, \fIint\fR rrclass, \fIstruct ub_result**\fR result);
108.LP
109\fIint\fR
110\fBub_resolve_async\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR name,
111.br
112 \fIint\fR rrtype, \fIint\fR rrclass, \fIvoid*\fR mydata,
113.br
114 \fIub_callback_t\fR callback, \fIint*\fR async_id);
115.LP
116\fIint\fR
117\fBub_cancel\fR(\fIstruct ub_ctx*\fR ctx, \fIint\fR async_id);
118.LP
119\fIvoid\fR
120\fBub_resolve_free\fR(\fIstruct ub_result*\fR result);
121.LP
122\fIconst char *\fR
123\fBub_strerror\fR(\fIint\fR err);
124.LP
125\fIint\fR
126\fBub_ctx_print_local_zones\fR(\fIstruct ub_ctx*\fR ctx);
127.LP
128\fIint\fR
129\fBub_ctx_zone_add\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR zone_name, \fIchar*\fR zone_type);
130.LP
131\fIint\fR
132\fBub_ctx_zone_remove\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR zone_name);
133.LP
134\fIint\fR
135\fBub_ctx_data_add\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR data);
136.LP
137\fIint\fR
138\fBub_ctx_data_remove\fR(\fIstruct ub_ctx*\fR ctx, \fIchar*\fR data);
139.SH "DESCRIPTION"
140.LP
141.B Unbound
142is an implementation of a DNS resolver, that does caching and
143DNSSEC validation. This is the library API, for using the \-lunbound library.
144The server daemon is described in \fIunbound\fR(8).
145The library can be used to convert hostnames to ip addresses, and back,
146and obtain other information from the DNS. The library performs public\-key
147validation of results with DNSSEC.
148.P
149The library uses a variable of type \fIstruct ub_ctx\fR to keep context
150between calls. The user must maintain it, creating it with
151.B ub_ctx_create
152and deleting it with
153.B ub_ctx_delete\fR.
154It can be created and deleted at any time. Creating it anew removes any
155previous configuration (such as trusted keys) and clears any cached results.
156.P
157The functions are thread\-safe, and a context an be used in a threaded (as
158well as in a non\-threaded) environment. Also resolution (and validation)
159can be performed blocking and non\-blocking (also called asynchronous).
160The async method returns from the call immediately, so that processing
161can go on, while the results become available later.
162.P
163The functions are discussed in turn below.
164.SH "FUNCTIONS"
165.TP
166.B ub_ctx_create
167Create a new context, initialised with defaults.
168The information from /etc/resolv.conf and /etc/hosts is not utilised
169by default. Use
170.B ub_ctx_resolvconf
171and
172.B ub_ctx_hosts
173to read them.
|
| 174Before you call this, use the openssl functions CRYPTO_set_id_callback and
175CRYPTO_set_locking_callback to set up asyncronous operation if you use
176lib openssl (the application calls these functions once for initialisation).
|
174.TP
175.B ub_ctx_delete
176Delete validation context and free associated resources.
177Outstanding async queries are killed and callbacks are not called for them.
178.TP
179.B ub_ctx_set_option
180A power\-user interface that lets you specify one of the options from the
181config file format, see \fIunbound.conf\fR(5). Not all options are
182relevant. For some specific options, such as adding trust anchors, special
183routines exist. Pass the option name with the trailing ':'.
184.TP
185.B ub_ctx_get_option
186A power\-user interface that gets an option value. Some options cannot be
187gotten, and others return a newline separated list. Pass the option name
188without trailing ':'. The returned value must be free(2)d by the caller.
189.TP
190.B ub_ctx_config
191A power\-user interface that lets you specify an unbound config file, see
192\fIunbound.conf\fR(5), which is read for configuration. Not all options are
193relevant. For some specific options, such as adding trust anchors, special
194routines exist.
195.TP
196.B ub_ctx_set_fwd
197Set machine to forward DNS queries to, the caching resolver to use.
198IP4 or IP6 address. Forwards all DNS requests to that machine, which
199is expected to run a recursive resolver. If the proxy is not
200DNSSEC capable, validation may fail. Can be called several times, in
201that case the addresses are used as backup servers.
202At this time it is only possible to set configuration before the
203first resolve is done.
204.TP
205.B ub_ctx_resolvconf
206By default the root servers are queried and full resolver mode is used, but
207you can use this call to read the list of nameservers to use from the
208filename given.
209Usually "/etc/resolv.conf". Uses those nameservers as caching proxies.
210If they do not support DNSSEC, validation may fail.
211Only nameservers are picked up, the searchdomain, ndots and other
212settings from \fIresolv.conf\fR(5) are ignored.
213If fname NULL is passed, "/etc/resolv.conf" is used (if on Windows,
214the system\-wide configured nameserver is picked instead).
215At this time it is only possible to set configuration before the
216first resolve is done.
217.TP
218.B ub_ctx_hosts
219Read list of hosts from the filename given.
220Usually "/etc/hosts". When queried for, these addresses are not marked
221DNSSEC secure. If fname NULL is passed, "/etc/hosts" is used
222(if on Windows, etc/hosts from WINDIR is picked instead).
223At this time it is only possible to set configuration before the
224first resolve is done.
225.TP
226.B
227ub_ctx_add_ta
228Add a trust anchor to the given context.
229At this time it is only possible to add trusted keys before the
230first resolve is done.
231The format is a string, similar to the zone\-file format,
232[domainname] [type] [rdata contents]. Both DS and DNSKEY records are accepted.
233.TP
234.B ub_ctx_add_ta_file
235Add trust anchors to the given context.
236Pass name of a file with DS and DNSKEY records in zone file format.
237At this time it is only possible to add trusted keys before the
238first resolve is done.
239.TP
240.B ub_ctx_trustedkeys
241Add trust anchors to the given context.
242Pass the name of a bind\-style config file with trusted\-keys{}.
243At this time it is only possible to add trusted keys before the
244first resolve is done.
245.TP
246.B ub_ctx_debugout
247Set debug and error log output to the given stream. Pass NULL to disable
248output. Default is stderr. File\-names or using syslog can be enabled
249using config options, this routine is for using your own stream.
250.TP
251.B ub_ctx_debuglevel
252Set debug verbosity for the context. Output is directed to stderr.
253Higher debug level gives more output.
254.TP
255.B ub_ctx_async
256Set a context behaviour for asynchronous action.
257if set to true, enables threading and a call to
258.B ub_resolve_async
259creates a thread to handle work in the background.
260If false, a process is forked to handle work in the background.
261Changes to this setting after
262.B ub_resolve_async
263calls have been made have no effect (delete and re\-create the context
264to change).
265.TP
266.B ub_poll
267Poll a context to see if it has any new results.
268Do not poll in a loop, instead extract the fd below to poll for readiness,
269and then check, or wait using the wait routine.
270Returns 0 if nothing to read, or nonzero if a result is available.
271If nonzero, call
272.B ub_process
273to do callbacks.
274.TP
275.B ub_wait
276Wait for a context to finish with results. Calls
277.B ub_process
278after the wait for you. After the wait, there are no more outstanding
279asynchronous queries.
280.TP
281.B ub_fd
282Get file descriptor. Wait for it to become readable, at this point
283answers are returned from the asynchronous validating resolver.
284Then call the \fBub_process\fR to continue processing.
285.TP
286.B ub_process
287Call this routine to continue processing results from the validating
288resolver (when the fd becomes readable).
289Will perform necessary callbacks.
290.TP
291.B ub_resolve
292Perform resolution and validation of the target name.
293The name is a domain name in a zero terminated text string.
294The rrtype and rrclass are DNS type and class codes.
295The result structure is newly allocated with the resulting data.
296.TP
297.B ub_resolve_async
298Perform asynchronous resolution and validation of the target name.
299Arguments mean the same as for \fBub_resolve\fR except no
300data is returned immediately, instead a callback is called later.
301The callback receives a copy of the mydata pointer, that you can use to pass
302information to the callback. The callback type is a function pointer to
303a function declared as
304.IP
305void my_callback_function(void* my_arg, int err,
306.br
307 struct ub_result* result);
308.IP
309The async_id is returned so you can (at your option) decide to track it
310and cancel the request if needed. If you pass a NULL pointer the async_id
311is not returned.
312.TP
313.B ub_cancel
314Cancel an async query in progress. This may return an error if the query
315does not exist, or the query is already being delivered, in that case you
316may still get a callback for the query.
317.TP
318.B ub_resolve_free
319Free struct ub_result contents after use.
320.TP
321.B ub_strerror
322Convert error value from one of the unbound library functions
323to a human readable string.
324.TP
325.B ub_ctx_print_local_zones
326Debug printout the local authority information to debug output.
327.TP
328.B ub_ctx_zone_add
329Add new zone to local authority info, like local\-zone \fIunbound.conf\fR(5)
330statement.
331.TP
332.B ub_ctx_zone_remove
333Delete zone from local authority info.
334.TP
335.B ub_ctx_data_add
336Add resource record data to local authority info, like local\-data
337\fIunbound.conf\fR(5) statement.
338.TP
339.B ub_ctx_data_remove
340Delete local authority data from the name given.
341.SH "RESULT DATA STRUCTURE"
342.LP
343The result of the DNS resolution and validation is returned as
344\fIstruct ub_result\fR. The result structure contains the following entries.
345.P
346.nf
347 struct ub_result {
348 char* qname; /* text string, original question */
349 int qtype; /* type code asked for */
350 int qclass; /* class code asked for */
351 char** data; /* array of rdata items, NULL terminated*/
352 int* len; /* array with lengths of rdata items */
353 char* canonname; /* canonical name of result */
354 int rcode; /* additional error code in case of no data */
355 void* answer_packet; /* full network format answer packet */
356 int answer_len; /* length of packet in octets */
357 int havedata; /* true if there is data */
358 int nxdomain; /* true if nodata because name does not exist */
359 int secure; /* true if result is secure */
360 int bogus; /* true if a security failure happened */
361 char* why_bogus; /* string with error if bogus */
362 int ttl; /* number of seconds the result is valid */
363 };
364.fi
365.P
366If both secure and bogus are false, security was not enabled for the
| 177.TP
178.B ub_ctx_delete
179Delete validation context and free associated resources.
180Outstanding async queries are killed and callbacks are not called for them.
181.TP
182.B ub_ctx_set_option
183A power\-user interface that lets you specify one of the options from the
184config file format, see \fIunbound.conf\fR(5). Not all options are
185relevant. For some specific options, such as adding trust anchors, special
186routines exist. Pass the option name with the trailing ':'.
187.TP
188.B ub_ctx_get_option
189A power\-user interface that gets an option value. Some options cannot be
190gotten, and others return a newline separated list. Pass the option name
191without trailing ':'. The returned value must be free(2)d by the caller.
192.TP
193.B ub_ctx_config
194A power\-user interface that lets you specify an unbound config file, see
195\fIunbound.conf\fR(5), which is read for configuration. Not all options are
196relevant. For some specific options, such as adding trust anchors, special
197routines exist.
198.TP
199.B ub_ctx_set_fwd
200Set machine to forward DNS queries to, the caching resolver to use.
201IP4 or IP6 address. Forwards all DNS requests to that machine, which
202is expected to run a recursive resolver. If the proxy is not
203DNSSEC capable, validation may fail. Can be called several times, in
204that case the addresses are used as backup servers.
205At this time it is only possible to set configuration before the
206first resolve is done.
207.TP
208.B ub_ctx_resolvconf
209By default the root servers are queried and full resolver mode is used, but
210you can use this call to read the list of nameservers to use from the
211filename given.
212Usually "/etc/resolv.conf". Uses those nameservers as caching proxies.
213If they do not support DNSSEC, validation may fail.
214Only nameservers are picked up, the searchdomain, ndots and other
215settings from \fIresolv.conf\fR(5) are ignored.
216If fname NULL is passed, "/etc/resolv.conf" is used (if on Windows,
217the system\-wide configured nameserver is picked instead).
218At this time it is only possible to set configuration before the
219first resolve is done.
220.TP
221.B ub_ctx_hosts
222Read list of hosts from the filename given.
223Usually "/etc/hosts". When queried for, these addresses are not marked
224DNSSEC secure. If fname NULL is passed, "/etc/hosts" is used
225(if on Windows, etc/hosts from WINDIR is picked instead).
226At this time it is only possible to set configuration before the
227first resolve is done.
228.TP
229.B
230ub_ctx_add_ta
231Add a trust anchor to the given context.
232At this time it is only possible to add trusted keys before the
233first resolve is done.
234The format is a string, similar to the zone\-file format,
235[domainname] [type] [rdata contents]. Both DS and DNSKEY records are accepted.
236.TP
237.B ub_ctx_add_ta_file
238Add trust anchors to the given context.
239Pass name of a file with DS and DNSKEY records in zone file format.
240At this time it is only possible to add trusted keys before the
241first resolve is done.
242.TP
243.B ub_ctx_trustedkeys
244Add trust anchors to the given context.
245Pass the name of a bind\-style config file with trusted\-keys{}.
246At this time it is only possible to add trusted keys before the
247first resolve is done.
248.TP
249.B ub_ctx_debugout
250Set debug and error log output to the given stream. Pass NULL to disable
251output. Default is stderr. File\-names or using syslog can be enabled
252using config options, this routine is for using your own stream.
253.TP
254.B ub_ctx_debuglevel
255Set debug verbosity for the context. Output is directed to stderr.
256Higher debug level gives more output.
257.TP
258.B ub_ctx_async
259Set a context behaviour for asynchronous action.
260if set to true, enables threading and a call to
261.B ub_resolve_async
262creates a thread to handle work in the background.
263If false, a process is forked to handle work in the background.
264Changes to this setting after
265.B ub_resolve_async
266calls have been made have no effect (delete and re\-create the context
267to change).
268.TP
269.B ub_poll
270Poll a context to see if it has any new results.
271Do not poll in a loop, instead extract the fd below to poll for readiness,
272and then check, or wait using the wait routine.
273Returns 0 if nothing to read, or nonzero if a result is available.
274If nonzero, call
275.B ub_process
276to do callbacks.
277.TP
278.B ub_wait
279Wait for a context to finish with results. Calls
280.B ub_process
281after the wait for you. After the wait, there are no more outstanding
282asynchronous queries.
283.TP
284.B ub_fd
285Get file descriptor. Wait for it to become readable, at this point
286answers are returned from the asynchronous validating resolver.
287Then call the \fBub_process\fR to continue processing.
288.TP
289.B ub_process
290Call this routine to continue processing results from the validating
291resolver (when the fd becomes readable).
292Will perform necessary callbacks.
293.TP
294.B ub_resolve
295Perform resolution and validation of the target name.
296The name is a domain name in a zero terminated text string.
297The rrtype and rrclass are DNS type and class codes.
298The result structure is newly allocated with the resulting data.
299.TP
300.B ub_resolve_async
301Perform asynchronous resolution and validation of the target name.
302Arguments mean the same as for \fBub_resolve\fR except no
303data is returned immediately, instead a callback is called later.
304The callback receives a copy of the mydata pointer, that you can use to pass
305information to the callback. The callback type is a function pointer to
306a function declared as
307.IP
308void my_callback_function(void* my_arg, int err,
309.br
310 struct ub_result* result);
311.IP
312The async_id is returned so you can (at your option) decide to track it
313and cancel the request if needed. If you pass a NULL pointer the async_id
314is not returned.
315.TP
316.B ub_cancel
317Cancel an async query in progress. This may return an error if the query
318does not exist, or the query is already being delivered, in that case you
319may still get a callback for the query.
320.TP
321.B ub_resolve_free
322Free struct ub_result contents after use.
323.TP
324.B ub_strerror
325Convert error value from one of the unbound library functions
326to a human readable string.
327.TP
328.B ub_ctx_print_local_zones
329Debug printout the local authority information to debug output.
330.TP
331.B ub_ctx_zone_add
332Add new zone to local authority info, like local\-zone \fIunbound.conf\fR(5)
333statement.
334.TP
335.B ub_ctx_zone_remove
336Delete zone from local authority info.
337.TP
338.B ub_ctx_data_add
339Add resource record data to local authority info, like local\-data
340\fIunbound.conf\fR(5) statement.
341.TP
342.B ub_ctx_data_remove
343Delete local authority data from the name given.
344.SH "RESULT DATA STRUCTURE"
345.LP
346The result of the DNS resolution and validation is returned as
347\fIstruct ub_result\fR. The result structure contains the following entries.
348.P
349.nf
350 struct ub_result {
351 char* qname; /* text string, original question */
352 int qtype; /* type code asked for */
353 int qclass; /* class code asked for */
354 char** data; /* array of rdata items, NULL terminated*/
355 int* len; /* array with lengths of rdata items */
356 char* canonname; /* canonical name of result */
357 int rcode; /* additional error code in case of no data */
358 void* answer_packet; /* full network format answer packet */
359 int answer_len; /* length of packet in octets */
360 int havedata; /* true if there is data */
361 int nxdomain; /* true if nodata because name does not exist */
362 int secure; /* true if result is secure */
363 int bogus; /* true if a security failure happened */
364 char* why_bogus; /* string with error if bogus */
365 int ttl; /* number of seconds the result is valid */
366 };
367.fi
368.P
369If both secure and bogus are false, security was not enabled for the
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367domain of the query.
| 370domain of the query. Else, they are not both true, one of them is true.
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368.SH "RETURN VALUES"
369Many routines return an error code. The value 0 (zero) denotes no error
370happened. Other values can be passed to
371.B ub_strerror
372to obtain a readable error string.
373.B ub_strerror
374returns a zero terminated string.
375.B ub_ctx_create
376returns NULL on an error (a malloc failure).
377.B ub_poll
378returns true if some information may be available, false otherwise.
379.B ub_fd
380returns a file descriptor or \-1 on error.
381.SH "SEE ALSO"
382\fIunbound.conf\fR(5),
383\fIunbound\fR(8).
384.SH "AUTHORS"
385.B Unbound
386developers are mentioned in the CREDITS file in the distribution.
| 371.SH "RETURN VALUES"
372Many routines return an error code. The value 0 (zero) denotes no error
373happened. Other values can be passed to
374.B ub_strerror
375to obtain a readable error string.
376.B ub_strerror
377returns a zero terminated string.
378.B ub_ctx_create
379returns NULL on an error (a malloc failure).
380.B ub_poll
381returns true if some information may be available, false otherwise.
382.B ub_fd
383returns a file descriptor or \-1 on error.
384.SH "SEE ALSO"
385\fIunbound.conf\fR(5),
386\fIunbound\fR(8).
387.SH "AUTHORS"
388.B Unbound
389developers are mentioned in the CREDITS file in the distribution.
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